1. Field of the Invention
This invention relates to a tape cassette adapter, more particularly to a tape cassette adapter which can convert a compact tape cassette, such as a 8 mm. camera video tape cassette, into a standard size tape cassette, such as a VHS or a Beta tape cassette, so as to apply the compact tape cassette to a general domestic video tape player.
2. Description of the Related Art
The invention is an improvement of a conventional tape cassette adapter, as shown in FIG. 1, which is used for converting a compact tape cassette 100 into a standard size tape cassette. The compact tape cassette 100 is smaller in size and lighter in weight than the standard size tape cassette.
The conventional tape cassette adapter includes a standard cassette case 11 which confines an upper opening 111 through which the compact tape cassette 100 can be placed into the standard cassette case 11, and a pivotable front cap 12 mounted on the standard cassette case 11. Two grooves are formed respectively in two opposite sides of the upper opening 111. A drive cover 13 has two opposite edges inserted slidably within the grooves of the upper opening 111 so as to close or open the upper opening 111. One of the opposite edges of the drive cover 13 is formed with a rack portion 131, as shown in FIG. 2.
Referring to FIGS. 1 and 2, the conventional tape cassette adapter further includes a tape draw-out unit which consists of a pair of fixing blocks 14, 15 and a pair of arms 16, 17, an arm-driving unit which consists of a first idle gear 101 and a first drive gear 102, and a reel drive unit which consists of a second drive gear 18 and a second idle gear 19.
The arms 16, 17 are mounted pivotally within the standard cassette case 11 and are movable operatively between first and second positions so as to draw the tape member 1001 of the compact tape cassette 100, by means of two rods 161, 171 secured on the end portions of the arms 16, 17, to form a predetermined tape path responsive to movement from the first position to the second position. The arm 16 has a lower fan tooth portion 162 formed thereon. The tape member 1001 of the compact tape cassette 100 is wound on a take-up reel 1002 and a support reel 1003 of the compact tape cassette 100.
The fixing blocks 14, 15 are mounted pivotally within the standard cassette case 11 and are restricted to move forward and backward automatically by means of two extension springs 105, 106. When moved to close the upper opening 111, the drive cover 13 can push the fixing blocks 14, 15 forward to position releasably the arms 16, 17 at their second positions in a known manner.
The first drive gear 102, which is mounted rotatably within standard cassette case 11, has a semi-circular tooth portion 1022 which engages the fan tooth portion 162 of the arm 16 and a circular tooth portion 1021 which engages the first idle gear 101 that in turn meshes with the rack portion 131 of the drive cover 13. Accordingly, when the drive cover 13 is moved to urge the first idle gear 101, the first drive gear 102 can be driven to swing the arm 16. At the same time, the movement of the drive cover 13 can also swing the arm 17 in a known manner.
The second drive gear 18, which is mounted pivotally within the standard cassette case 11, meshes with an inner tooth portion 192 of the second idle gear 19 and is equipped with a pulley 181. A belt 104 is associated with the pulley 181 and a pulley 1031 of a third drive gear 1032. The third drive gear 1032 is mounted rotatably on one end of a clutch rod 103 and engages the rack portion 131 of the drive cover 13. The other end of the clutch rod 103 is pivoted to the standard cassette case 11. When the drive cover 13 is moved forward, the clutch rod 103 and the third drive gear 1032 are moved forward to loosen the belt 104 and thus, the second drive gear 18 is not rotated thereby. At the same time, the arm 16 is turned to its second position by rotation of the first drive gear 102 and the first idle gear 101. When the drive cover 13 is moved backward, the belt 104 is tightened by rearward movement of the third drive gear 1032 and the clutch rod 103 to rotate the second drive gear 18 and the second idle gear 19. In this way, an outer tooth portion 191 of the second idle gear 19, which engages the take-up reel 1002 of the compact tape cassette 100, can drive the take-up reel 1002 to wind the tape member 1001 of the compact cassette case 100 from the predetermined tape path to the compact tape cassette 100 prior to removal of the compact cassette case 100 from the standard cassette case 11.
The drawbacks of the conventional tape cassette adapter are as follows:
1. Owing to its complicated construction, more particularly to the arm-driving unit which includes many gears, the conventional tape cassette adapter easily breaks down after a long-term use. Of course, it is difficult to manufacture the conventional tape cassette adapter.
2. When the drive cover 13 is moved forwardly to turn the arm 16 to its second position so as to draw the tape member 1001 from the compact tape cassette 100 to form a predetermined tape path, the tape member 1001 is easily overdrawn from the compact tape cassette 100 due to the moment of inertia on the take-up reel 1002 and the reel drive unit. Thus, when the second drive gear 18 of the reel drive unit is driven by means of a domestic video tape player to rotate take-up reel 1002 in order to wind the tape member 1001, a strong tensile stress is formed on the overdrawn tape member 1001 so that the tape member 1001 may easily snap.